RESUMEN
Endophytic microflora is source of several bioactive compounds. Endophytes isolated from Coleus species are yet to be fully explored for their bioactive potential. In this study, bacterial endophytes were isolated from three different species of Coleus. Isolated endophytes were characterized by using Gram staining and by sequencing 16S rRNA region. Further, solvents with different polarities were used to prepare extracts which were used for assessment of different bio-activities including in vitro cytotoxicity, anti-microbial and anti-oxidant activities. Also, the pure endophytic bacterial cultures were evaluated for their antiphytopathogen potential as well as indole-3-acetic acid (IAA) and protease production. Advanced studies on the endophytes with promising activities may lead to the isolation of novel natural products for drugs as well as in industrial and agricultural applications.
RESUMEN
We assessed fluconazole susceptibility in 52 Candida tropicalis clinical strains using seven antifungal susceptibility methods, including broth microdilution (BMD) [standard M27 A3 (with neutral and acid pH), ATB Fungus 3, Vitek 2 system and flow cytometric analysis] and agar-based methods (disk diffusion and E-test). Trailing growth, detection of cell-associated secreted aspartic proteases (Saps) and morphological and ultrastructural traits of these clinical strains were also examined. The ranges of fluconazole 24 h-minimum inhibitory concentration (MIC) values were similar among all methods. The essential agreement among the methods used for MIC determinations was excellent and all methods categorised all strains as susceptible, except for one strain that showed a minor error. The presence of the trailing effect was assessed by six methods. Trailing positivity was observed for 86.5-100 percent of the strains. The exception was the BMD-Ac method where trailing growth was not observed. Morphological and ultrastructural alterations were detected in C. tropicalis trailing cells, including mitochondrial swelling and cell walls with irregular shapes. We tested the production of Saps in 13 C. tropicalis strains expressing trailing growth through flow cytometry. Our results showed that all of the C. tropicalis strains up-regulated surface Sap expression after 24 h or 48 h of exposure to fluconazole, which was not observed in untreated yeast strains. We concluded that C. tropicalis strains expressing trailing growth presented some particular features on both biological and ultrastructural levels.